Project description:# Background Acute kidney injury (AKI) in sepsis patients increases patient mortality. Endothelial cells are important players in the pathophysiology of sepsis-associated AKI (SA-AKI), yet knowledge regarding their spatiotemporal involvement in coagulation disbalance and leukocyte recruitment is lacking. This study investigated the identity and kinetics of responses of different microvascular compartments in kidney cortex in response to SA-AKI. # Methods Laser microdissected arterioles, glomeruli, peritubular capillaries, and postcapillary venules from kidneys of mice subjected to cecal ligation and puncture (CLP) were analyzed using RNA sequencing. Differential expression and pathway enrichment analyses identified genes involved in coagulation and inflammation. A selection of these genes was evaluated by RT-qPCR in microvascular compartments of renal biopsies from patients with SA-AKI. The role of two identified genes in lipopolysaccharide-induced endothelial coagulation and inflammatory activation were determined in vitro in HUVEC using siRNA-based gene silencing. # Results CLP-sepsis in mice induced altered expression of approximately 400 genes in the renal microvasculature, with microvascular compartments exhibiting unique spatiotemporal responses. In mice, changes in gene expression related to coagulation and inflammation were most extensive in glomeruli at early and intermediate time points, with high induction of Plat, Serpine1, Thbd, Icam1, Stat3, and Ifitm3. In human SA-AKI, PROCR and STAT3 were induced in postcapillary venules, while SERPINE1 expression was diminished. IFITM3 was increased in arterioles and glomeruli. In vitro studies revealed that STAT3 and IFITM3 partly control endothelial coagulation and inflammatory activation. # Conclusion Renal microvascular compartments in mice and humans exhibited heterogeneous changes in coagulation- and inflammation-related gene expression in response to SA-AKI. Additional research should aim at understanding the functional consequences of the here described heterogeneous microvascular responses to establish the usefulness of identified genes as therapeutic targets in SA-AKI.

Project description:Liver is uniquely capable to repair itself after injury. Multiple molecular and biochemical processes initiated after partial hepatectomy, lead to proliferation of all cells within the liver. MicroRNAs (miRNAs) are a class of highly abundant non-coding RNA molecules that cause post-transcriptional gene repression and are involved in several biological processes including cell cycle regulation and differentiation. We examined the expression levels of miRNAs in liver tissue received from control mice (L0) and compared them with the corresponding levels in liver tissue 12 hours after liver regeneration induced by 2/3 partial hepatectomy (L12). MicroRNA expression was investigated using microRNA profiling. Further qPCR analysis was used for validation of the differentially expressed microRNAs at an early stage of liver regeneration, induced by 2/3 partial hepatectomy. TargetScan and Gene Ontology (GO) analysis was performed in order to identify the possible miRNA target genes and their ontology, respectively. A subset of miRNAs were found to be differentially expressed during liver regeneration. Mmu-miR-21 and mmu-miR-30b* showed the higher levels of up-regulation in liver tissue from the hepatectomized mice at the end of the experiment (L12) compared to the sham operated mice (L0). Mmu-miR-21 up-regulation was further confirmed by qPCR. In situ hybridization (ISH) revealed that mmu-miR-21 exhibited the higher levels of expression at 12 hours post hepatectomy. On the contrary, mmu-miR-34c*, mmu-miR-144, mmu-miR-207, mmu-miR-207, mmu-miR-451, mmu-miR-582-3p and mmu-miR-290-5p exhibited <0.5 down-regulation in liver tissue after partial hepatectomy in L12 vs. L0 mice. Microarrays and qPCR results were in good agreement (Pearson correlation = 0.881). Our results provide important information regarding how microRNAs are deferentially expressed in murine liver tissue before and after partial hepatectomy. The early up-regulation of mmu-miR-21 during the process of liver regeneration suggests a regulatory role in liver regeneration in vivo.

Project description:Liver is uniquely capable to repair itself after injury. Multiple molecular and biochemical processes initiated after partial hepatectomy, lead to proliferation of all cells within the liver. MicroRNAs (miRNAs) are a class of highly abundant non-coding RNA molecules that cause post-transcriptional gene repression and are involved in several biological processes including cell cycle regulation and differentiation. We examined the expression levels of miRNAs in liver tissue received from control mice (L0) and compared them with the corresponding levels in liver tissue 12 hours after liver regeneration induced by 2/3 partial hepatectomy (L12). MicroRNA expression was investigated using microRNA profiling. Further qPCR analysis was used for validation of the differentially expressed microRNAs at an early stage of liver regeneration, induced by 2/3 partial hepatectomy. TargetScan and Gene Ontology (GO) analysis was performed in order to identify the possible miRNA target genes and their ontology, respectively. A subset of miRNAs were found to be differentially expressed during liver regeneration. Mmu-miR-21 and mmu-miR-30b* showed the higher levels of up-regulation in liver tissue from the hepatectomized mice at the end of the experiment (L12) compared to the sham operated mice (L0). Mmu-miR-21 up-regulation was further confirmed by qPCR. In situ hybridization (ISH) revealed that mmu-miR-21 exhibited the higher levels of expression at 12 hours post hepatectomy. On the contrary, mmu-miR-34c*, mmu-miR-144, mmu-miR-207, mmu-miR-207, mmu-miR-451, mmu-miR-582-3p and mmu-miR-290-5p exhibited <0.5 down-regulation in liver tissue after partial hepatectomy in L12 vs. L0 mice. Microarrays and qPCR results were in good agreement (Pearson correlation = 0.881). Our results provide important information regarding how microRNAs are deferentially expressed in murine liver tissue before and after partial hepatectomy. The early up-regulation of mmu-miR-21 during the process of liver regeneration suggests a regulatory role in liver regeneration in vivo. Twenty male wild type mice C57BL6J (8 weeks old) fed a standard diet were used for the liver regeneration experiment. Mice were housed in the animal facility of the University of Patras Medical School in temperature-, light- and humidity-controlled rooms with a 12-h light/dark cycle. All animal procedures were approved by the institutional review board of the University of Patras Medical School and were in accordance with EC Directive 86/609/EEC. A 2/3 partial hepatectomy (PH) was performed on 10 mice according to a recently published standardized protocol whereby the median and left lobes of the liver were removed and another 10 sham operated mice were used as the control group. The liver was allowed to regenerate and mice were sacrificed 12 hours after operation. Liver samples were collected from the sham operated mice (L0) and the hepatectomized mice at the end of the experiment (L12).

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MRNA data - Unique miRNome and Transcriptome Profiles Underlie Microvascular Heterogeneity in Mouse Kidney

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